Nested Lens Frame Structure for Endoscope Optical Alignment
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Solution Overview
Problem
Existing image pickup apparatuses in endoscopes face challenges in accurately holding optical lenses, leading to optical performance deterioration due to misalignment and increased assembly complexity, particularly in the distal end portion where a solid image pickup device is integrated with a group of lenses.
Innovation Solution
The design incorporates a lens frame structure with a step portion and a fitting portion that reduces contact area and insertion resistance, allowing precise alignment and assembly of lenses, while a moving lens frame and adjustable components ensure stable optical precision and reduced risk of lens breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional lens holding structure with multiple lens frames is used, then optical performance can be maintained, but assembly complexity and difficulty increase significantly
Solution Approach 1:
The lens holding structure is divided into multiple lens frames (first lens frame, second lens frame, third lens frame) that can be assembled together. Each frame holds specific lenses and can be independently positioned and secured, allowing complex optical alignment to be broken down into manageable segments rather than requiring a single monolithic structure.
Solution Approach 2:
The lens frames are nested within each other in a concentric arrangement, with the second lens frame positioned inside the first, and the third lens frame positioned inside the second. This nested configuration allows multiple lens groups to be held in a compact space while maintaining independent adjustability of each frame's optical position.
2Reliability
If multiple lens frames are used to hold lenses, then optical performance is maintained, but assembly workability deteriorates
Solution Approach 1:
The lens frames are designed with movable and adjustable characteristics, allowing them to be positioned and secured in different configurations during assembly. The frames can be dynamically adjusted to achieve proper optical alignment and then secured in place, providing both flexibility during manufacturing and stability during operation.
Solution Approach 2:
The lens frames are pre-assembled with lenses mounted on them before being integrated into the final optical system. This preliminary assembly allows for quality control and alignment verification at the frame level before integration, simplifying the overall assembly process and improving workability.
3Manufacturing precision
If lenses are held by multiple lens frames, then optical precision is maintained, but the risk of lens breakage increases
Solution Approach 1:
By dividing the lens holding function across multiple separate frames rather than using a single structure, each lens is supported by its own dedicated frame. This segmentation provides better mechanical protection for each lens individually, reducing the risk of breakage while maintaining precise optical positioning through the adjustable nature of each frame.
Data Source
AI summary
A second lens frame has a shape including: a contact portion having a cylindrical shape with a diameter smaller than an inner diameter of a space portion of a first lens frame, a distal end portion thereof being brought into contact with an end face of the first lens frame; and a fitting portion having a diameter larger than that of the contact portion in a cylindrical shape fitting on an inner wall surface of the first lens frame, and when the second lens frame is inserted into the space portion of the first lens frame, a gap is formed therebetween. Accordingly, a distal end portion of the second lens frame is reliably brought into contact with an end face of a flange portion of the first lens frame, whereby variations in position in an optical axis direction are eliminated, enabling provision of a stable optical precision.